linux-kernel - Re: [PATCH] objtool: Don't fail the kernel build on fatal errors

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Date:   Fri, 15 Jan 2021 10:45:01 -0800
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Miroslav Benes <mbenes@...e.cz>, Borislav Petkov <bp@...e.de>,
        Julien Thierry <jthierry@...hat.com>
Subject: Re: [PATCH] objtool: Don't fail the kernel build on fatal errors

On Thu, Jan 14, 2021 at 2:46 PM Josh Poimboeuf <jpoimboe@...hat.com> wrote:
>
> This is basically a revert of commit 644592d32837 ("objtool: Fail the
> kernel build on fatal errors").
>
> That change turned out to be more trouble than it's worth.  Failing the
> build is an extreme measure which sometimes gets too much attention and
> blocks CI build testing.
>
> These fatal-type warnings aren't yet as rare as we'd hope, due to the
> ever-increasing matrix of supported toolchains/plugins and their
> fast-changing nature as of late.
>
> Also, there are more people (and bots) looking for objtool warnings than
> ever before, so such warnings not likely to be ignored for long.
>
> Suggested-by: Nick Desaulniers <ndesaulniers@...gle.com>
> Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>

Thank you; I feel the arguments against enabling -Werror for the
kernel apply here.  The warnings are annoying enough that we plan to
follow up on them all.
Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>

> ---
>  tools/objtool/check.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index 5f8d3eed78a1..4bd30315eb62 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -2928,14 +2928,10 @@ int check(struct objtool_file *file)
>         warnings += ret;
>
>  out:
> -       if (ret < 0) {
> -               /*
> -                *  Fatal error.  The binary is corrupt or otherwise broken in
> -                *  some way, or objtool itself is broken.  Fail the kernel
> -                *  build.
> -                */
> -               return ret;
> -       }
> -
> +       /*
> +        *  For now, don't fail the kernel build on fatal warnings.  These
> +        *  errors are still fairly common due to the growing matrix of
> +        *  supported toolchains and their recent pace of change.
> +        */
>         return 0;
>  }
> --
> 2.29.2
>


-- 
Thanks,
~Nick Desaulniers